Sheet-metal pole-arm.



C. L. PEIRCE, JR.

SHEET METAL POLE ARM.

APPLICATION FILED MAY 4. 1914.

1 1 75,077. Patented Mar. 14, 1916.

[N VEN TOR.

WITNESSES.- y 2 0. 1 y I MM ATTORNEYS.

CHARLES Ir. :PEIRCE, JR., OF PITTSBURGH, PENNSYLVANIA.

SHEET-METAL POLE-ABM.

Specification of Letters Patent.

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Application filed May 4, 1914. Serial No. 836,113.

7 '0 all whom it may concern.

Be it known that l, Cr-ninnns L. Pniucn, Jr., a citizen of the UnitedStates, and a resident of Pittsburgh, in the county of Allegheny andState of Penney vania, have invented certain new and useful Improvementsin Sheet-Metal Pole-Arms, of which the following is a specification.

My invention relates to sheet metal pole arms and contemplates improvedconstruction better adapted to the need of the present day in theelectrical. field.

The tendency at the present time is to get away from wooden pole armschiefly because such arms are unable to withstand the severe strains towhich they would be sub jected under service in heavy power work.Furthermore, wood is an uncertain commodity and such uncertainty shouldnot exist particularly in high tension service work. Pole arms have beenconstructed of commercial forms of iron and steel, as for example anglebar, channel bar, or pipe, but in order to get the necessary strengththese arms were made of heavy stock, there being an over suiiiciency ofiron or steel but not the proper distribution thereof to get thestrength where desired. The tendency is also to use steel pins inconnection with metal arms in order to have all metal insulatorsupports.

The general object of my invention is to I produce metallic pole armswhich require less metal but which have better distribution thereof andgreater strength than metal arms heretofore used.

More in detail, the main object of the invention is to build up a polearm of sheet metal and of such form that it will be very light yetexceedingly strong, and the cost of manufacture will be greatly reduced.

In connection with the old type of pole arms built up of'commercialformssuch as angle iron, channel iron, pipe, or the like, where themetal isof considerable thickness, straps could readily be used to secure pinsto the arms. However, where the arm is built up of sheet metal which iscomparatively thin, straps might have a tendency to crush the metal, andanother object is therefore to provide such form of sheet metal arm aswill enable pins to be rigidly secured thereto by short ordinary boltsor hook bolts.

Generally speaking, the pole arm of my invention comprises a channelshaped body bent up of sheet metal which is secured to a fiat base orcross arm engaging wall, this base projecting beyond the edges of thebody to form flanges about whose edge hook bolts may engage or which maybe provided with bolt holes for receiving bolts to secure pins to thearm, and other holes may be provided in the flanges in order that bracesmay be secured to the arm.

Sheet metal pole arms have been constructed heretofore, see myco-pending application Serial No. 737,366, filed Decei ber 18, 1912.However, in tie construction in this col-pendin application the pins areapplied in the ordinary manner, that is, holes are provided in the topwall through which the shanks of pins proj set. with this arrangementthe pins cannot always be economically secured, and furthermore,downward service strain or pressure on the pins is in a plane offsetfrom the vertical plane of support of the arm on the pole, the armtherefore tending to twist under very heavy loads. However, my improvedconstruction involves the clamping of pins against the pole engagingbase of the arm which will bring the downward service pressure on thepins into the vertical plane of the arm support on the pole, and wherethe arm is set in a gain provided in the pole the downward pressure onthe pins will be in the plane of the gain and the bolts supporting thearm will be relieved of considerable strain.

The various features of the invention will be clearly understood byreference to the accompanying sheet of drawings in which Figure 1 is aperspective 'iew of part of a pole with my improved cross arm structureapplied thereto, Fig. 2 is a rear view of one end of the arm showingmore clearly the manner of securing a pin thereto, Figs. 3, a and 5 areend views of the showing modified forms of body therefor; 6 is an endview showing another modified arrangement, and Fig. 7 is an end viewshowing still another modified arrangement.

The arm comprises essentially a body part 10 bent into generally convexform from a strip of sheet metal, and a base 11 in the form of a band ofsheet metal, this base be ing preferably fiat. In the forms shown inFigs. 1 to 5 the channel shaped body part 10 has the flat end sectionsor flanges 10 and 10 and the longitudinal edge sections 11 and 11 of thebase are curled over to intimately surround the flanges 10 and 10. Afterthus securing the body and base together they may be ri 'idly securedtogether by means of rivets engaging through the flanges and curled oversections, but preferably spot welcnng is resorted to to secure the endsrigidly together so that there is ab solutelv no chance for any relativemove mentbetween the body part and base. If the body and base were notsecured together and any relativ movement were possible the arm couldtwist and would close under heavy strain. However, by securing the edgesor" the parts together the structure is just asrigid as though it wereformed integrally. At suitable intervals the flange sections of thestructure may be punched to provide bolt holes 12 for the purpose oisecuring pins thereto or for the purpose of bolting the upper ends ofbraces 13 to the arm. The arm is secured to a pole such as p by means ofthrough bolts or lag screws 14 and 15 passing through the center boltholes provided in the upper and lower flanges of the structure. v -Therethe pole is flat the arm is usually secured with its base against theflat face of the pole. lVhen applied to an ordinary cylindrical woodenpole as shown in Fig. 1, a gain 16 is usually cut into the pole intowhich the rm is set. In Figs. 1 and 2 l have shown pins 17 securedagainst the outer face of the base 11 by means of bolts 18 and 19passing through the upper and lower flanges of the structure. With thisarrangement of the pins, the weight and pressure thereon will besubstantially in the plane of the connection of the arm with the pole,that is, the pressure on the pins is substantially in the plane oi thebase 11, and in the plane of the gain 16. Such positioning of the pinswill prevent twisting tendency of the arm under very heavy weight. Theconvex body part 10 by being rigidly secured to the base will act as abrace to prevent bending of the arm, either vertically or horizon--tally. Yet, in order to withstand these strains the sheet metal used canbevery thin, this bemg on account of the rigid structure described.Furthermore, the arm will be very hght and can be readily handled.

It can also be manufactured very cheaply and the cost or" shipping isgreatly reduced on account of its llghtness.

The insulator pins shown do not them selves form part of this inventionbut they are particularly adaptable for use in connec tion with the armdescribed. The pins shown are each bent up oi a length of channel ironto leave along the lower end thereof the slot 20 of a width suliicientto receive the bolts 18 and 19 for securing them to the arm structure.

In Figs. 3, 4E and 5 body parts of modified shape are shown. In Fig. 3the body 10 instead of being semi-circular as in Fig. 1, is of U-shapecross-section. In Fig. 4 the body 10 is of V-shape cross section and inthe layers are intimately secured Fig. 5 the body 1O is also of V-shapecross section except that the top wall .90 is horizontal. In each of theforms shown in Figs. 3, l and 5, the body part has the upper and lowerflat sections or flanges 10 and 10 intimately received by the curledover edges 11 and 11 of the fiat base 11to form seams of which together,preferably by welding.

In Fig. 6 is shown a semi-circular body 10 with the end flanges 10 and10 but the base 11 does not have its longitudinaledges curled over as inFigs. 1 to 5, thetlang es 10 and 10 engaging the base along its straightedges and being welded thereto.

In Fig. 7 another form is shown which is particularly adaptable forreceiving the hooked ends of bolts for securing pins to the structure.As shown, the body part 10 has again the longitudinal flanges 1O" and 10while the base 11 has the short flanges 11 and 11 extending at rightangles from the baseand beyond the flanges 10 and 10*, these flangesbeing secured to the base preferably by welding. The projecting edges offlanges 11 and 11 serve to. receive the hooked ends 6 of fasteningmembers extending from the pins. As shown, the pin 21 has a bracket 22secured thereto whose hooked end e receives the edge of the upper flange11 of the arm structure while at the lower end a bolt 23 passes throughthe pin whose hooked end 6 receives the edge of the lower flange 11 Whenthe pin is to be applied the bracket 22 is hooked over the top edge 11and the bolt 23 then slipped through the hole from the front and the nut2% applied and the pin locked in place. t is evident, of course, thateither brackets or bolts couldbe used both above and below.

I do not of course desire to be limited to V the exact constructions,forms. or treatments shown and described as modifications may bepossible which would still come within the scope of the invention.

I claim the following:

1. A pole'arm structure comprising a base in the form of a fiat piece ofthin sheet metal, a sheet metal strengthening member of arch shapedcross section extending full length of said base and having its edge sections deflected into a common plane to engage the base adjacent theedges thereof, said deflected edges of the strengthening member beingrigidly secured to the base throughout the extent thereof to formflanges for receiving insulator supports, and insulator supports securedto said flanges.

2. A pole arm structure comprising a base in the form of a strip ofsheet metal, a sheet metal strengthening member of arch shaped crosssection extending full length of said base and having its edge sectionsdeflected outwardly to .a common plane to engage with said base, thelongitudinal edge sections of said base being bent over to Copies ofthis patent may be obtained for overlap said strengthening member edge15 sections, the engaging sections of the base and strengthening memberbeing rigidly secured together throughout the length of the arm andhaving bolt holes therethrough, and insulator supporting pins secured tothe 20 back of the base by bolts passing through said holes.

In witness whereof, I hereunto subscribe my name this 27 day of April,A. D., 1914.

CHARLES L. PEIRCE, JR.

lVitnesses:

CHARLES J. SCHMIDT,

S. B. CARR.

five cents each, by addressing the Commissioner of Patents, Washington,D. G.

